This research project has anatomical and physiological specific aims. The physiological specific aim concerns the functional attributes of ventral root afferent fibers. The anatomical specific aims are aimed at elucidating organizational patterns of the fine fibers of the peripheral nervous system and spinal cord. In particular, the number and types of propriospinal fibers in the tract of Lissauer and the spinal cord in general will be determined. The ratio of preganglionic fibers to postganglionic cells in the sympathetic nervous system will be determined and the branching of sensory axons in the peripheral nerve will be assessed.